Morcos M, et al. - Researchers ascertained if late radiotherapy treatment can prevent the progression of heterotopic ossification (HO) following total hip arthroplasty (THA). In order to identify the patients who developed HO following THA and were treated with late radiotherapy, a chart review was performed. Progression of HO in patients who unexpectedly develop significant HO following THA could be effectively prevented with late, low-dose radiotherapy. Overall, the mean total area of HO was increased by 19 mm ² (2%).